Sitemaps help inform search engines of how to index and search your site. They also allow sub-pages to show up better in search results, as it informs the search engine of which pages are important. Mobile site maps can be a bit tricky, as often Google may not see the site map on the mobile specific URL. Additionally DudaMobile does not provide a way for you to add your own custom site map.
Luckily, Google accounts for this by providing a method to link to mobile specific pages along side the desktop pages. What you need to do is update the existing desktop Sitemap with the mobile page URLs that associate with the same page on your desktop site.